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Updated: Jan 12, 2026

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis
Published on: February 18, 2020
Autoinhibitory calcium ATPases regulate the calcium gradient required for rapid polarized growth
Samantha E Ryken1, Shu-Zon Wu1, Matias L Lee2
1Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
None:
Polarized growth drives the morphogenesis of elongated cellular structures. In plants, polarized growth depends on actin and a tip focused ionic calcium gradient. How the calcium gradient is maintained remains unclear. We discovered that autoinhibitory calcium ATPases (ACAs) redundantly contribute to the steepness of the calcium gradient. ACA1 and ACA2 localize to the subapical plasma membrane and ACA5 to the vacuole membrane, providing spatial regulation of calcium efflux. Tip-growing plant cells also exhibit apical calcium fluctuations. Even though Δaca1/2/5 cells have a diminished calcium gradient, they exhibit normal fluctuations and actin but have significantly reduced apical secretion. Furthermore, cells lacking apical actin retain a strong calcium gradient but have reduced apical secretion. Suppression of both the calcium gradient and apical actin dramatically impairs growth, supporting a model where two independent and parallel processes, the calcium gradient and apical actin, promote rapid polarized growth.
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